The present invention relates to an underground heat exchanging apparatus for carrying out various functions such as cooling, heating, refrigerating and hot water feeding by effectively utilizing the excellent heat conservation and the huge heat capacity underground.
As is well known, underground temperatures are maintained at a stable level throughout all seasons and are little affected by atmospheric temperature. In practice the underground zone located at a distance of 5 to 6 meters as measured from the ground surface has a substantially consant temperature. It has been found as a result or practical measurements that the surface temperature of the ground varies as atmospheric temperature varies but that the temperature at a deep, underground position is higher in the winter than in the summer. This is attributable to a huge heat capacity underground. During summer, this surface zone of the ground is warmed under hot sunshine and thus stored thermal energy is gradually transmitted to a deep zone underground with the time delay in the winter to heat the latter, and thereby resulting in the above-mentioned peculiar phenomenon. This means that temperature in the deep zone in the underground is kept at a level opposite to that in the atmosphere due to time lag in the transmittance of thermal energy. Thus, the underground has more stable temperature in the deeper zone but as the depth as measured from the ground surface increases further, underground temperatures gradually increase due to the influence of heat conduction from the magma layer in the earth. It should be noted that heat exchanging is achieved quickly because of underground water.